QTL Detection for Milk Fatty Acids in French Dairy Cattle

Abstract Text: Milk fatty acid (FA) composition was estimated from mid infrared spectrometry (MIR) for more than 450,000 test-day from 86,458 cows in the three French Montbeliarde (MO), Normande (NO) and Holstein (HO) breeds, within the PhénoFinlait project. 23 FA expressed in percentage of milk or fat were analyzed. 6867 cows were genotyped with the 50K Illumina chip and QTL detection was carried out within breed by Linkage and Linkage Disequilibrium Analysis. In each breed, on average 11 QTL were detected per trait for saturated FA, vs 6 for unsaturated FA. Chromosomes 14, 5, and 19 affected many traits. Chromosomes 1, 11, 17, 26, and 27 were very influential on some traits. The same regions frequently affected many FA, as illustrated with chromosome 5. A high QTL conservation was observed across breeds.

Keywords: dairy cattle, milk fatty acids, QTL detection